As anyone who has seen Ingmar Bergman’s Persona (1966) can attest, it is a film nearly impossible to define. Or perhaps it is so open to interpretation, that its “meaning” is in the end, irrelevant. According to Thomas Elsaesser’s essay in the new Criterion Collection Blu-ray edition of Persona, “Besides Citizen Kane, it is probably the most written-about film in the canon.”

Like Kane, the plot of Persona is deceptively simple. In mid-sentence, an actress goes mute onstage during a play, and never speaks again. A nurse is hired to try and bring her back from whatever dark place she has gone, apparently to no avail. Elisabet Vogler (Liv Ullmann) is the famous actress who is being cared for by Nurse Alma (Bibi Andersson), and it is just the two of them onscreen for almost the entire movie.

There is a composer who once said that music is not the notes, but what happens between the notes. He was speaking of the use of silence, but the sensibility applies to Bergman’s film as well. Documenting the “story” of Persona simply does not do it justice. The thought I have always had about it is that by the end, Elisabet and Alma have merged into one person. There is also a very strong possibility that the two are mirror images of each other.

In any event, most of the “action” takes place at a small beach cottage that Alma takes Elisabet to in her attempt to break through the psychological wall. Elisabet clearly hears and understands what Alma is saying, and Ullman’s silent acknowledgement of this is brilliantly portrayed. Alma tries everything, telling Elisabet stories, offering opinions, observing her, and being frustrated at every turn.

The story of the time Alma cheated on her husband, and participated in a fumbling orgy with a friend and two young men they had just met is incredible. Not that it is a particularly lurid event, in fact, calling it an “orgy” is pushing things. The four of them dropped their inhibitions momentarily, and got caught up in it all. But in telling what amounts to her darkest secret to this complete stranger, Alma has made herself more vulnerable than she ever has before. And even this elicits no response. Elisabet just sits there and listens.

Shortly afterward, Alma is going into town, and Elisabet hands her some letters to send. The one to her husband is unsealed, and Alma cannot resist opening and reading it, once she is away from the cottage. In the letter, Elisabet has told her husband all about the “simple” nurse, and mocks her for her “orgy story.” It is a shocking betrayal that we as the viewers feel as strongly as Alma does.

Alma is incensed, and the film reaches its climax when she returns to confront Elisabet. Some critics have called Persona a modern horror story, which is certainly one way of looking at it. I tend more toward the idea of it being a psychological drama, but no matter. What I have described is just the bare bones of this Bergman masterpiece, it is a film that must be seen to be appreciated. And even then, multiple viewings are recommended.

As usual, Criterion offer a plethora of supplemental features. The first of these is “A Persona Prologue” (20:00), which is an incredible visual essay by Bergman scholar Peter Cowie, focusing on the first seven minutes of the film. Cowie argues that this prologue is a microcosm of not only Persona, but of Bergman’s career itself.

There are four interview segments, the earliest of which features Andersson, Ullmann, and Bergman on Swedish television in 1966, discussing the newly-released Persona (19:33). The following interview is a solo Bergman excerpt from Canadian TV in 1970, in which he recalls that the inspiration for Persona came during a stay in the hospital. (8:12). The Criterion Collection interviewed Ullmann in 2013 about her portrayal of Elisabet Vogler (16:07). The final interview was also done in 2013 for Criterion, with filmmaker Paul Schrader (10:58).

“On Set Footage” features behind-the-scenes footage shot during the production, and features audio commentary from Bergman scholar Birgetta Steene (18:06). And, as if all of that were not enough, there is the 2012 feature-length documentary “Liv and Ingmar,” which takes an in-depth at the actress and director’s five-decade relationship (84:00). Finally we get the original theatrical trailer for Persona (2:43).

Persona is in black and white, with English subtitles. The Blu-ray transfer is beautiful, at a 1.37:1 aspect ratio. The original monaural soundtrack was remastered at 24-bit from the 17.5 mm magnetic track, and sounds exquisite as well.

One of the keys to Persona is established in the prologue, in which the lines between reality and dreams are blurred. This theme continues throughout the interactions between Alma and Elisabet, until the hard, ugly, and violent reality forces its way through. For anyone with an appreciation for film who has not seen Persona, do it now. I find new things in it with every viewing, and it has never looked better than it does on this Criterion Collection Blu-ray edition.